No abstract

In order to respect the new fleet-wide average emission regulations, recent studies show that car manufacturers produce an increased number of electric vehicles. For improving the dynamic performances of an electric vehicle while maintaining a low energy consumption, different solutions are used, such as the multi-speed transmission, or the continuously variable transmission (CVT). Another solution more advantageous than other EV typologies consists of a dual motor two speed direct drive, that implies each motor being connected with the final drive through a separate gear. The aim of this paper is to analyse the energy consumption and the overall transmission performance in different test cycles for a middle class with different configurations. The study was carried out by developing a model in a performant simulation environment. The obtained simulation results from the chosen configuration are compared in different test cycles in terms of energy consumption ratio (ECR) and vehicle speed fluctuation (VSF) with the ones from a direct drive EV and a two-gear transmission EV.

To reduce the CO2 emission level for the new CAFE regulations, it is mandatory that automobile producers should choose the hybridization approach. Relevant published literature show that for a mild hybrid passenger car, increased values of the hybridization factor (HF) have marginal influence over the fuel economy for high speed values if a fixed ratio e-gearbox is used. This paper analyzes the energetic consumption for a Through the Road Hybrid Vehicle (TTR-HEV) when using a two-gear ratio transmission for the electric axle. To investigate the energetic performances, a complex model developed in a performant simulation environment is used. The energetic consumption is determined for five different test cycles in terms of speed and duration by analyzing the fuel consumption ratio (FCR) for different values of the HF. In order to compare the test cycles, the FCR parameter is used, after which the correlation with vehicle speed fluctuation (VSF) is explored. The simulation results obtained for the current application are compared with a hybrid vehicle equipped with a single gear in the rear axle. The results are also expressed in terms of CO2 emission.